全文获取类型
收费全文 | 18116篇 |
免费 | 1783篇 |
国内免费 | 414篇 |
专业分类
耳鼻咽喉 | 49篇 |
儿科学 | 211篇 |
妇产科学 | 215篇 |
基础医学 | 3324篇 |
口腔科学 | 264篇 |
临床医学 | 1970篇 |
内科学 | 2124篇 |
皮肤病学 | 122篇 |
神经病学 | 1777篇 |
特种医学 | 310篇 |
外国民族医学 | 1篇 |
外科学 | 931篇 |
综合类 | 2963篇 |
现状与发展 | 4篇 |
一般理论 | 1篇 |
预防医学 | 2103篇 |
眼科学 | 157篇 |
药学 | 1945篇 |
136篇 | |
中国医学 | 1019篇 |
肿瘤学 | 687篇 |
出版年
2024年 | 63篇 |
2023年 | 288篇 |
2022年 | 583篇 |
2021年 | 878篇 |
2020年 | 833篇 |
2019年 | 572篇 |
2018年 | 545篇 |
2017年 | 656篇 |
2016年 | 724篇 |
2015年 | 816篇 |
2014年 | 1351篇 |
2013年 | 1455篇 |
2012年 | 1239篇 |
2011年 | 1188篇 |
2010年 | 976篇 |
2009年 | 935篇 |
2008年 | 933篇 |
2007年 | 830篇 |
2006年 | 739篇 |
2005年 | 623篇 |
2004年 | 492篇 |
2003年 | 376篇 |
2002年 | 321篇 |
2001年 | 294篇 |
2000年 | 265篇 |
1999年 | 198篇 |
1998年 | 196篇 |
1997年 | 147篇 |
1996年 | 174篇 |
1995年 | 152篇 |
1994年 | 111篇 |
1993年 | 120篇 |
1992年 | 108篇 |
1991年 | 90篇 |
1990年 | 79篇 |
1989年 | 95篇 |
1988年 | 98篇 |
1987年 | 51篇 |
1986年 | 67篇 |
1985年 | 80篇 |
1984年 | 103篇 |
1983年 | 55篇 |
1982年 | 80篇 |
1981年 | 62篇 |
1980年 | 61篇 |
1979年 | 53篇 |
1978年 | 37篇 |
1977年 | 29篇 |
1976年 | 41篇 |
1973年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
71.
细胞凋亡是在一定的生理或病理条件下。由基因控制的细胞自我毁灭过程。凋亡异常与许多疾病(尤其是肿瘤)的形成及发展进程密切相关。细胞凋亡调控机制研究证明。多种基因(如P53、C-myc、Bcl-2、Bax等)参与了细胞凋亡的调控过程。TFAR19基因是由我国科研人员最近新发现的另一重要的凋亡相关基因,笔者主要就其结构特点、性质功能、临床意义作一概述。 相似文献
72.
73.
Richard M. Pearson 《Clinical & experimental optometry》1990,73(6):172-177
A simple but reliable method was used to measure the axial edge lift at the total diameter over a range of back optic zone radii of several proprietary designs of rigid gas-permeable corneal lens. One of these was found to have a constant axial edge lift construction. 相似文献
74.
J. N. Laverri re J. L. Richard A. Morin N. Buisson A. Tixier-Vidal W. B. Huttner D. Gourdji 《Molecular and cellular endocrinology》1991,80(1-3):41-51
Secretogranin I (SgI; chromogranin B) belongs to a class of acidic tyrosine-sulfated secretory proteins believed to play a role in the secretory process of endocrine cells. Our aim here was to compare the levels of SgI mRNA to that of prolactin (PRL) and growth hormone (GH), using rat pituitary cell lines. As far as the constitutive expression is concerned, we found a positive correlation between SgI mRNA and PRL mRNA levels. However, the neuropeptide TRH (50 nM) inhibited the accumulation of SgI mRNA in GH3B6 cells whereas, as expected, it induced a rapid and sustained increase in PRL mRNA accumulation. By contrast, 17β-estradiol (1 nM) stimulated the accumulation of both SgI and PRL mRNAs, with the same EC50 (18–59 pM). Reciprocally, treatment with dexamethasone (100 nM) reduced the level of SgI and PRL mRNAs to 23% and 29% of control, respectively, but led to a 2.1-fold increase in the GH mRNA level. Altogether, the present work shows that SgI gene expression is subject to multiple hormonal regulations and occasionally parallels the regulation of the PRL gene but never that of the GH gene, under the conditions tested. 相似文献
75.
76.
Brigitte Schiller Chun He David J. Salant Alice Lim Jessy J. Alexander Richard J. Quigg 《The Journal of experimental medicine》1998,188(7):1353-1358
Crry (complement receptor 1–related protein/gene y) is a key cellular complement regulator in rodents. It is also present in Fx1A, the renal tubular preparation used to immunize rats to induce active Heymann nephritis (HN), a model of membranous nephropathy. We hypothesized that rats immunized with anti-Fx1A develop autoantibodies (auto-Abs) to Crry as well as to the megalin-containing HN antigenic complex, and that anti-Crry Abs promote the development of injury in HN by neutralizing the complement regulatory activity of Crry. Rats immunized with Fx1A lacking Crry remained free of proteinuria and glomerular deposits of C3 during a 10-wk follow-up despite typical granular immunoglobulin (Ig)G deposits in glomeruli. Anti-Fx1A auto-Abs were present in their sera at levels that were not different from sera pooled from proteinuric rats with HN induced with nephritogenic Fx1A. Passive administration of sheep anti-Crry Abs to rats immunized with Crry-deficient Fx1A led to proteinuria and glomerular C3 deposition, which were not seen in such rats injected with preimmune IgG, nor in rats with collagen-induced arthritis injected with anti-Crry IgG. To directly examine the role of Crry in HN, rats were immunized with Crry-deficient Fx1A reconstituted with rCrry. This led to typical HN, with 8 out of 15 rats developing proteinuria within 14 wk. Moreover, the extent of glomerular C3 deposition correlated with proteinuria, and anti-Crry Abs were present in glomerular eluates. Thus, Crry is a key nephritogenic immunogen in Fx1A. Formation of neutralizing auto-Abs to Crry impairs its function, leading to unrestricted complement activation by Abs reactive with the HN antigenic complex on the epithelial cell surface. 相似文献
77.
大鼠烧伤后急性期蛋白mRNA的表达 总被引:2,自引:0,他引:2
分析了不同烧伤程度大鼠肝、脾、肾和骨骼骨内4种急性期蛋白,即a1-酸性糖蛋白、a1-抗胰蛋白酶、白蛋白和转铁蛋白(Trf)mRNA水平的动态变化特征,结果表明:(1)肝脏是合成各种APR的主要场所;(2)即使是小面积的烧伤也可以诱发急性期反应。(3)烧伤后血清Alb水平下降是急性期反应的特征,但在mRNA水平上并不下降而是增加。 相似文献
78.
A longitudinal model based on the simplex model is presented to analyze simultaneously means and covariance structure using univariate longitudinal twin data. The objective of the model is to decompose the mean trend into components which can be attributed to those genetic and environmental factors which give rise to phenotypic individual differences and a component of unknown constitution which does not involve individual differences. Illustrations are given using simulated data and repeatedly measured weight obtained in a sample of 82 female twin pairs on six occasions. 相似文献
79.
80.
Studiesonthefunctionandregulationoflow-affinityglucocorticoidreceptor¥LeYingying(乐颖影);XuRenbao(徐仁宝)(DepartmentofPathophysiolo... 相似文献